The Tank, Cruiser, Mk II (A10), was developed alongside the A9, and was intended to be a heavier, infantry tank version of that type. In practice, it was not deemed suitable for the infantry tank role and was classified as a "heavy cruiser".

The A10 was developed by Sir John Carden of Vickers in 1934 by the adaptation of his A9 design. The A10 specification called for armour of up to 1 inch (25 mm) standard (the A9 was 14 mm (0.55 in)); a speed of 10 mph (16 km/h)) was acceptable.[2] The two sub-turrets present on the A9 were removed, and extra armour bolted onto that already present on the front and sides of the hull, along with all faces of the turret, providing approximately twice the armour in most areas. The A10 was two tonnes heavier than the A9, but used the same 150 bhp engine, and as a consequence the tank's top speed was cut from 25 miles per hour (40 km/h) to 16 miles per hour (26 km/h).

The turret armament consisted of a QF 2-pounder (40-mm) gun and a coaxial .303Vickers machine gun. For the production version there was a 7.92 mmBESA machine gun mounted in the hull in a barbette to the right of the driver. This was added to give extra firepower but at the expense of simplicity - the Vickers and the BESA using different ammunition. The tank had a total crew of five (Commander, gunner, loader, driver and hull machine gunner), and there was no separation between the driver's compartment and the fighting compartments.

The prototype ("Tank, Experimental A10E1") was completed in 1936, a few months after the A9 prototype. Carden had died in an air crash in 1935 and development was slower than expected. In 1937, the A10 was dropped as an infantry support tank, but in 1938 it was decided to produce it as a "heavy cruiser".

The A10 was accepted for service - initially as "Tank, Cruiser, Heavy Mk I" and then "Tank, Cruiser A10 Mk 1" and finally "Tank, Cruiser Mk II". Production was ordered in July 1938. Total production was 175 vehicles, including the 30 CS versions (see below); 45 were built by Birmingham Railway Carriage and Wagon Company, 45 by Metropolitan-Cammell, 10 by Vickers. In late 1939, another order was placed with Birmingham Railway Carriage and Wagon Company, this time for a larger order of 75 vehicles. - entering service in December 1939, but was something of an oddity - it had been intended to sacrifice speed for armour like an Infantry tank, but was still relatively poorly armoured, and was, as a result, not effective.

A British Cruiser Mk II disabled by having lost a track (seen lower right) in Greece, 1941.

A number of Mark IIs were part of the British Expeditionary Force (BEF) sent to France in the early stages of World War II. The cross country performance was recorded as poor, but they were still used later in North Africa at the defence of Tobruk in 1941, where reliability and suspension performance in the desert conditions was praised. Sixty worn out examples were taken to Greece by the 3rd Royal Tank Regiment and, although they performed well against the German tanks, over 90% were lost due to mechanical breakdowns as opposed to enemy action (mainly lost tracks).[3][4]

Had a 3.7 inches (94 mm) howitzer in the turret instead of the 2 pdr. The standard ammunition load was 40 rounds smoke, and a few HE shells. The CS denotes Close Support.

This weapon was derived from a World War I field howitzer, the QF 3.7-inch mountain howitzer. It was not related to the 3-inch howitzer used in later British tanks in World War II, which was itself replaced by a 95 mm (3.7 in) howitzer in the later versions of the Churchill infantry tanks and all CS versions of the Centaur and Cromwell cruiser tanks. British doctrine was that the CS tank was to provide smoke cover in advances or retreats and hence many more smoke rounds were carried than HE.[5]